使用btn-large，.btn-sm或.btn-xs类可使用具有任何按钮大小的下拉菜单。
让我们看一个btn-large的例子
<!DOCTYPE html> <html> <head> <title>Bootstrap Example</title> <link href = "/bootstrap/css/bootstrap.min.css" rel = "stylesheet"> <script src = "/scripts/jquery.min.js"></script> <script src = "/bootstrap/js/bootstrap.min.js"></script> </head> <body> <div class = "btn-group"> <button type = "button" class = "btn btn-default dropdown-toggle btn-lg" data-toggle = "dropdown"> Default <span class = "caret"></span> </button> <ul class = "dropdown-menu" role = "menu"> <li><a href = "#">Action</a></li> <li><a href = "#">Another action</a></li> <li><a href = "#">Something else here</a></li> <li class = "divider"></li> <li><a href = "#">Separated link</a></li> </ul> </div> </body> </html>